Sensitized compounds and elements

ABSTRACT

The sensitivity of radiation-sensitive polyyne compounds may be extended to wavelengths in the x-ray region by the use of organometallic sensitizers, such as triphenylbismuthine and hexaphenyldilead, for example. High-speed direct-imaging x-ray elements may thus be obtained.

United States Patent Ehrlich SENSITIZED COMPOUNDS AND ELEMENTS [75] Inventor: Sanford H. Ehrlich, Rochester, NY. [73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Jan. 14, 1972 [21] App1.-No.: 217,979

[52] US. Cl. 96/88 [51] Int. Cl G03c 1/00 [58] Field of Search 96/90 R, 90 PC, 88

[5 6] References Cited UNITED STATES PATENTS 3,501,302 3/1970 Foltz 96/48 R 1 May 21, 1974 3,501,303 3/1970 Foltz et a1. 96/48 R 3,501,308 3/1970 Adelman 96/48 R 3,501,297 3/1970 Cremeans 96/48 R Primary ExaminerNormanG. Torchin Assistant Examiner-Richard L. Schilling Attorney, Agent, or Firm-James L. Lewis [5 7] ABSTRACT The sensitivity of radiation-sensitive polyyne compounds may be extended to wavelengths in the x-ray region by the use of organometallic sensitizers, such as triphenylbismuthine and hexaphenyldilead, for example. High-speed direct-imaging x-ray elements may thus be obtained.

22 Claims, N0 Drawings 1 SENSITIZED COMPOUNDS AND ELEMENTS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION In general, this application relates to radiant-energy sensitive compositions comprising crystalline polyacetylenic compounds suitable for image-recording purposes. More particularly, this invention concerns enhancing the sensitivity of such radiant energy sensitive compositions through the utilization of particular sensitizing materials, and includes the enhanced radiationsensitive compositions and the technique of preparation.

It has now been discovered that the sensitivity of polyacetylenic compounds to radiographic energy may be substantially increased by the presence of organometallic sensitizers. High-speed direct-imaging x-ray elements which are essentially insensitive to conventional room light may thus be provided.

DESCRIPTION OF THE PRIOR ART Numerous polyacetylenic compositions of matter are reported in the literature along with observations that some undergo color change upon exposure to light and- /or ultra-violet radiation. Included among investigators reporting on polyyne compositions are: Arthur Seher; Ferdinand Bohlmann and his coauthors; and E. R. H. Jones and M. C. Whiting and their coauthors. The photosensitive polyacetylenic compounds taught in the art typically contain a minimum of two acetylenic linkages as a conjugated system (i.e., C E CC E C), and with only a few exceptions, carbon atoms in alpha positions to the acetylenic carbon atoms, i.e., those carbon atoms directly connecting to the acetylenic carbon atoms are bonded directly only to carbon and or hydrogen atoms. These photosensitive polyacetylenic compositions of matter encompass diynes, triynes, tetraynes, higher polyynes and numerousderivatives'and related compounds thereof of various chemical classes ranging from hydrocarbon compounds to acids, esters, and diols, to still other compounds of other chemical classifications containing numerous and varied organic radicals. A

As is apparent from publications of the aforementioned investigators, methods are known in the art for the preparation of polyacetylenic compositions. Methods also are taught in U.S. Pat. Nos. 2,8l6,l49; 2,941,014, 3,065,283; etc. General preparative methods include: oxidative coupling or 'oxidative dehydrocondensation reactions of numerous terminal acetylenic compounds to prepare, as desired, symmetrical and unsymmetrical polyyne compounds; dehydrohalogenation reactions to provide compounds containing acetylenic bonds; and variations, modifications and combinations of such two reactions to provide preparative routes for a multitude of polyacetylenic compositions of matter.

From the preceding description of the art and the sources therein mentioned, there are apparent numerous polyyne compounds which may be suitable for use in this invention. For some there is a brief mention of radiation sensitivity, generally in the ultraviolet range, while for others nothing is reported as to radiation sensitivity. However, it is within the skill of the art to readily evaluate a polyynes sensitivity to any given radiation where the same is unknown. Thus, one needs merely to expose samples of a prepared crystalline polyacetylenic composition of matter to various forms of radiant energy and upon exposure to observe whether a visible color change occurs in the exposed composition. If a visible color change occurs upon exposure to a form of radiant energy, then the crystalline polyacety- Ienic composition of matter is deemed sensitive, for purposes of the present invention, to that specific form of radiant energy.

Radiant energy, as used herein, is intended to include numerous variant forms of radiant energy, encompassing not only the ultraviolet and visible regions, i.e., actinic radiation and infrared region of the electromagnetic spectrum, but also electron beams, such as developed by cathode ray guns, gamma-rays, x-rays, betarays, electrical corona discharge, and other forms of corpuscular and/or wave-like energy generally deemed to be radiant energy. The various individual crystalline polyacetylenic compositions of concern generally are not responsive to all such forms of radiant energy, but selectively respond to at least one or more of several variant forms thereof. Within the numerous and varied useful crystalline polyacetylenic compositions of matter, some respond rapidly and selectively to certain radiant energy forms,'and slowly or not at all to other forms of radiant energy. Most frequently, response to a particular form of radiant energy is greatest, and most rapid, at particular narrow regions and wavelengths of the electromagnetic spectrum. Generally, the preferred polyacetylenic compositions are most sensitive to radiation within the ultraviolet region.

Depending on particular requirements for a desired application, such as temperature of use, radiant energy form employed, desired speed of response, desired color of image, and the like, there is presently available a wide selection of useful radiation-sensitive crystalline polyacetylenic compositions of matter for use in imagerecording applications. However, as previously noted, polyacetylenic compositions have in the past been highly sensitive to ultraviolet radiation, and less sensitive to radiation of other wavelengths. Although some of the polyynes comprising the materials described in the priorart are inherently photosensitive, their degree of sensitivity is usually low, and greatest sensitivity usually occurs in a narrow wavelength portion of the spectrum, so that it is desirable to add materials to increase sensitivity and to shift sensitivity toward the desired longer wavelength portion of the spectrum. Increasing the sensitivity of such systems in the x-ray region of the spectrum has several advantages: it makes available inexpensive and convenient light-stable x-ray film; it reduces x-ray exposure time; and it provides print-out film for x-ray usage.

It is, therefore, an object of our invention to provide a novel class of sensitizers for radiation-sensitive systems which produces an unusual increase in sensitivity and extends the range of sensitivity into the x-ray wavelengths of the spectrum.

Another object is to provide a novel class of sensitizers for crystalline polyacetylenic compositions.

It is another object to provide useful sensitized compositions comprising a radiation-sensitive crystalline polyacetylenic compound and a compound which increases the x-ray sensitivity of the polyacetylenic compound.

A further object is to provide processes for the preparation of sensitized compositions, for employment of the same in image-recording applications, and for processing exposed sensitized compositions in various applications.

SUMMARY OF THE INVENTION These and other objects are obtained by the practice of this invention, which invention resides in the use of radiation-sensitive compositions comprising a crystalline polyacetylenic compound and sensitizing organometallic compounds such as triphenylbismuthine and hexaphenyldilead. Additional suitable sensitizing organometallic compounds include such phenyl substituted materials as [(C H Sn] Te; (C H GeTeSn(C H B Sh M G m; s 5) ]2 s 4)2 g; C H HgOCOCH and (C H Te Other organometallic compounds such as nC H HgOCOCH may also be employed.

In general, such organometallic compounds have been found to be useful sensitizers. However, it should be noted that each does not necessarily provide the same enhancement of x-ray sensitivity. This is particularly true in regards to different classifications or classes of polyacetylenic compounds. Whereas certain compounds may provide relatively little enhancement of the sensitivity of an alkali metal salt of a polyacetylenic dioic acid, the same material may provide a large enhancement of the x-ray sensitivity of an alkylamide derivative of polyacetylenic polyoic acid. Similarly, other organometallics may have little effect upon alkylamide derivatives of polyacetylenic compounds, but may greatly enhance the sensitivity of polyacetylenic amine salts, or urethane derivatives of diyne diols.

The enhancement provided by the specific organometallic compound employed as a sensitizer for the polyyne compound is evidenced by the sensitized composition being able to undergo a significant color change upon exposure to a wavelength of radiant energy other than that to which it was principally sensitive in its unsensitized form, or to undergo said color change at a significantly lower level of radiation. For example, a polyyne compound particularly sensitive to ultraviolet radiation of 2,537 A wavelength may possess little or no significant sensitivity to normal daylight. After sensitizing such a polyyne compound with a suitable material, such as by comingling the two, the resultant sensitized crystalline composition possesses a significant sensitivity to normal daylight. Often this providing of significant daylight photosensitivity is accompanied by little or no appreciable loss of the polyynes initial ultraviolet sensitivity. Similarly, the x-ray sensitivity enhancement provided by the organometallic compounds disclosed herein is accompanied by a deeper color change and/or faster speed of response to the sensitized composition to x-ray radiation with no decrease in inherent ultraviolet sensitivity.

The sensitized compositions of this invention are prepared by comingling with each other a radiationsensitive polyacetylenic compound and an organometallic compound, such as previously described. This comingling should provide intimate contact between at least some of the employed polyacetylenic compound and the sensitizer.

A number of suitable polyacetylenic compositions of matter for utilization in the process and elements of this invention are disclosed in US. Pat. No. 3,501,302. The polyacetylenic compositions described therein include photosensitive crystalline acid derivatives, and in par ticular, certain esters and salts of dicarboxylicterminated polyacetylenic compounds having the structural formula HOOC (CH (-C I C),,(CH,--),,,2-COOH, wherein n is an integer of at least 2 and m and m 2 are integers, not necessarily the same but preferably the same, greater than 5 and less than 10. Thepreferred photosensitive crystalline acid derivatives disclosed by said patents include: the monoand diesters of these diacids, and especially of the symmetrical diacetylenic diacids, with particular preference for the lower alkyl esters, and most specifically the alkyl ester derivatives wherein the alkyl-ester moiety contains less than three carbon atoms; and alkali metal salts and acid derivatives of these diacids and their half-esters, particularly the potassium salt of the methyl half-ester of the preferred symmetrical diacetylenic diacids. Particularly preferred is the monomethyl ester of 10,12-docosadiynedioic acid.

Further polyacetylenic compositions which are suitable for utilization according to this invention include alkylamide derivatives such as those which have the structural formula A-.(CH ),(C C),,--(CH ),,B, wherein: n is an integer greater than l; x and y are each an integer from O to l0; A may be a methyl radical, either unsubstituted or substituted, (such as methoxymethyl or ethoxymethyl), COOR, CONHR, CONHNHR" or CONHCONHR", and B is a radical selected from the group consisting of CONHR, CONHNHR", and CONHCONHR", wherein R may be' H or an alkyl of less than eight carbon atoms (e.g., methyl, propyl, pentyl, octyl, etc.), R is an alkyl having from two to 12 carbon atoms, (e.g., propyl, butyl, octyl,. decyl, undecyl, etc.), including substituted alkyls such as hydroxy, polyhydroxy, amino, substituted amino, alkyl thio, COOR, CONHR, or methoxy substituted alkyl, and R" may be phenyl or an alkyl having from 2 to 12 carbon atoms. Preferred alkylamides of this nature include: methyl 2l-[ N-(- 3carboxypropyl )carbamoyl l O,- l2heneicosadiyne; methyl 2 l [N( 3- hydroxypropyl )carbamoyl] l 0, l 2heneicosadiynoate; and methyl 2l-[N--(3-carboxypropyl)carbamoyl]10,12-heneicosadiynoate.

Suitable radiation-sensitive crystalline polyacetylenic amine salts may have the structural formula B+CH- +,(C C ),.+CH ),,COOA wherein: n is an integer greater than 1; x and y are each an integer from 0 to 10; A is selected from gmmonium and substituted a mmonium groups, (e.g., NH R, NH RR Nl-lRR R NRR'R R"); B is selected from the group consisting of CH COOA", COOR, CONl-IR, CONHNHR, CONHCONHR, ROOCNH, and RNHCOO radicals, wherein R, R, R and R may be the same or different, and may be H, alkyl (including hydroxy or methoxy substituted alkyl), or aryl, R may be l-lor an alkyl of less than eight carbon atoms (e.g., methyl, propyl, pentyl, octyl, etc.), R is an alkyl of from 2 to l2 carbon atoms (e.g., propyl, butyl, octyl, decyl, undecyl, etc.), including substituted alkyl suchas hydroxy, polyhydroxy, amino, substituted amino, alkyl thio, carboxy, or methoxy substituted alkyl, R may be phenyl or an alkyl having from two to 12 carbon atoms, and R is an alkyl, including methoxy or hydroxy substituted alkyls of from one to eight carbon atoms, phenyl, or hydroxy substituted phenyl. Suitable polyacetylenic amine salts include hexylammonium 20--(N--hexylcarbamoyl)- 9, l l -eicosadiyne-1-carboxylate, propylammonium N propylcarbamoyl)9,l l-- eicosadiyne l carboxylate, and 3-hydroxypropylammonium 20-N-(3hydroxypropylcarbamoyl)-9,l l-eicosadiyne l-carboxylate.

Additional suitable polyacetylenic compounds include polyacetylenic bis urethanes corresponding to the formula [R-NHCOO(CH ),,C C1 wherein n is an integer of 1 to 4, and R is selected from the group consisting of alkyl radicals of from one to 12 carbon atoms, including substituted alkyl radicals such as hydroxy, polyhydroxy, amino, substituted amino, or methoxy substituted alkyl, phenyl and substituted phenyl radicals (e.g., hydroxy, carboxy, and methoxy phenyl). Suitable members of this class of polyacetylenic compounds include 2,4-hexadiyne-l,6-diol bis (N- hexylurethane), and 2,4hexadiynel,6diol bis(l\lbutylurethane).

In the practice of the invention there is employed an image-receptive element comprising a carrier means which serves to fixedly position crystals of the radiation-sensitive crystalline polyacetylenic composition. The carrier means functions to hold individual crystals in fixed position in relation to other crystals so that the element, unexposed and exposed, can be handled and moved without displacement and change in position of crystals with respect to each other. I The carrier means can be in any of several diverse embodiments. Generally, the carrier means comprise a binder material, such as a natural or synthetic plastic, resin, colloid or gel and the like, wherein the crystals of the photosensitive crystalline polyacetylenic composition of matter are dispersed and held in fixed position. In such instances, the polyyne composition may be mixed as a dope, solution, emulsion, dispersion or the like with the binder material and then processed to provide solid films, sheets, coatings, and the like containing dispersed crystals of the sensitive polyacetylenic composition. Thus, one embodiment of the imagereceptive element is a solid sheet, film, or the like, comprising a binder material as a dispersing medium to position fixedly therein crystals of the radiation-sensitive polyacetylenic composition. Another embodiment of the element is a support material or body to which adheres a film, coating, or the like of the binder material having the dispersed cyrstals therein. Useful support materials include paper sheet, glass sheet, plastic film, and other conventional and suitable photographic quality support materials. Still an additional embodiment of the element may comprise the support material having adhered thereto a binder-free coating of the crystals of the sensitive polyacetylenic composition of matter. Other element embodiments, as desired, may include a suitable photographic coating material on one or more surfaces and interfaces of the various element embodi ments. In addition. other embodiments may comprise polyyne crystals and support means of any of various combinations of the several foregoing components and still other components apparent to those in the art, so long as the carrier means fixedly positions the radiation-sensitive crystalline polyacetylenic composition.

Exemplary support materials include: vitreous materials, such as glass, glazed ceramics, porcelain, etc.; fibrous materials, such as cardboard, fiberboard, paper including bond paper, resin and clay-sized papers, wax or other transparentized paper, paperboard, etc.; cloths and fabrics including those of silk, cotton, viscose rayon, etc.; metals, such as copper, bronze, aluminum,

tin, etc.; natural polymers and colloids, such as gelatin and polysaccharides; natural and synthetic waxes, including paraffin, beeswax, camauba wax; synthetic resins and plastics, including particularly polyethylene, polypropylene, polymers and copolymers of vinylidene and vinyl monomers including polyvinyl chloride, polyvinylidene chloride, vinyl chloride/vinyl acetate, vinyl acetate/acrylate, vinyl acetate/methacrylate, vinyli dene chloride/acrylonitrile, vinylidene chloride/vinyl acetate, vinylidene chloride/methacrylate, polystyrenes, polyvinyl acetals including polyvinyl butyral, polyvinyl formal, polyvinyl alcohol, polyamides including polyhexamethylene adipamides, N-methoxymethyl polyhexamethylene adipamide, natural and synthetic rubbers including butadiene-acrylonitrile copolymers,

2chloro-l,3butadiene polymers, polyacrylate polymers and copolymers including polymethylmethacrylate, polyethylmethacrylate, polyurethanes, polycarbonates, polyethylene terephthalate, polyethylene terephthalate/isophthalate copolymers and other esters, such as obtained by condensing terephthalic acid and its derivatives with propylene glycol, diethylene glycol, tetramethylene glycol or cyclohexanel 4-dimethanol, cellulose ethers including methyl cellulose, ethyl cellulose and benzyl cellulose, cellulose esters and mixed esters including cellulose acetate, triacetate, cellulose propionate, cellulose nitrate and cellulose diacetate; and even nonthermoplastic materials including cellulose, phenolic resins, melamineformaldehyde resins, alkyd resins, thermosetting acrylic resins, epoxy resins, and numerous other synthetic resins, and plastics as will be apparent to those skilled in the art. 1 g

The base'or support material may be transparent, translucent, or opaque, and should be selected with due consideration being given to the particular radiant energy to which the employed crystalline polyacetylenic compound is sensitive. It is also selected with due consideration of the intended usage of the imaged element and of the specific radiant energy and technique to be employed in the particular image-recording application. For example, where the imaging technique requires transmission of x-ray radiation through the support to expose the polyacetylenic crystals, the support should possess such a transmission characteristic. The base or support may be adhered directly to the radiation-sensitive crystals, or indirectly adhered, if desired, by a subbing layer or coating for any of several purposes, e.g., to alter the supports transmission of the radiant energy, to change the supports reflectivity of the radiant energy, to modify adherence to the support or for other reasons. Similar to the support material, such subbing layer is selected with due regard to the specific radiant energy and technique to be employed in the particular image-recording application. Subbing layers for various photographic purposes and methods of coating supports with the same are well known.

Generally and preferably the element, is a flat film, sheet, plate or the like, so as to present a flat surface upon which the radiant energy may be directed. However, curvedsurfaced and other than flat-surfaced elements, although generally of lesser utility, are not excluded.

Exemplary binder materials of utility as components for the carrier means include: natural and synthetic plastic resins, waxes, colloids, gels and the like including gelatins, desirably photographic-grade gelatin, various polysaccharides including dextran, dextrin, hydrophylic cellulose ethers and esters, acetylated starches, natural and synthetic waxes including paraffin, beeswax, polyvinylacetals, polymers of acrylic and methacrylic esters and amines, hydrolyzed interpolymers of vinyl acetate and unsaturated addition polymerizable compounds such as maleic anhydride, acrylic and methyacrylic esters and styrene, vinyl acetate polymers and copolymers and their derivatives, including completely and partially hydrolyzed products thereof, polyvinyl acetate, polyvinyl alcohol, polyethylene oxide polymers, polyvinylpyrrolidene, polyvinyl acetals including polyvinyl acetaldehyde acetal, polyvinyl butyraldehyde acetal, polyvinyl sodium-o-sulfobenzaldehyde acetal, polyvinyl formaldehyde acetal, and numerous other known photographic binder materials including a substantial number of aforelisted useful plastic and resinous support materials which are capable of being placed in the form of a dope, solution, dispersion, gel, or the like for incorporation therein of the radiationsensitive polyacetylenic composition and are then capable of processing to a solid form containing dispersed crystals of the polyacetylenic composition. As is well known in the art, in the preparation of smooth uniform continuous coatings of binder materials, there may be employed therewith small amounts of conventional coating aids as viscosity controlling agents, leveling agents, dispersing agents, and the like. The particular binder material employed is selected with due regard to the specific radiant energy and technique to be employed in the particular image-recording application and invariably is a binder material permitting substantial transmission of that specific radiant energy to be employed. Desirably, the binder material is a nonsolvent, or possesses only limited solvating properties for the polyyne so that the polyyne is capable of existence in its radiation-sensitive crystalline form therein.

Well-known sources, optical systems, camera arrangements, focusing and projection systems and the like for the desired radiant energy are used in employing the image-receptive element in the varied imageforming applications. The resultant images are directly formed print-out images in that they can be seen by the human eye to be a distinctly different color than unirradiated crystals of the element.

A material substantially nontransmissive of the radiant energy may be laid on the image-forming element,v

allowing the applied radiant energy to strike the element according to the desired image or images. If desired,the subject need not contact the element, with the radiant energy being projected to pass through the transmissive portion of the subject to strike the element.

Thus, an object, whose image is to be obtained, may be placed between the radiant energy source and the element and the radiant energy striking the element will be of an image pattern dependent on the radiant energy absorption and transmission characteristics of the particular absorption. Materials such as taught herein are of particular value for industrial nondestructive testing by x-ray examination of such things as metal castings, turbine blades, aircraft structures, welds, etc.

Where the imaged elements are to be retained for lengthy periods, desirably they are stored, as in an en velope or opaque container,'in a manner excluding any stray irradiation of radiant energy of a form affecting the element. This may also be effectively accomplished by overcoating the imaged element with a layer of material which absorbs radiation to which the element is sensitive. Thus, an ultraviolet absorbing layer may be coated over the imaged element. Alternatively, the initially imaged elements may be fixed or converted to a more stable imaged state. In fixing, the unexposed crystalline polyyne is placed in a form in which it is no longer substantially radiation-sensitive, as by solvating it in the binder, changing it fromcrystalline to liquid state, or washing it out from the element, and the like. In conversion, the initial irradiation induced color is often transformed to another distinctly different color,

which is relatively stable to exposure to the initial form of radiant energy inducing the image formation.

A particularly convenient manner to effect a color transformation of the initially induced image is to carefully heat the imaged element to an appropriate ele vated temperature, generally between 520C less than the melting point of the nonirradiated crystalline polyyne, at which temperature the initial radiantenergy induced color-transformed crystals and crystal portions transform to a distinctly difierent color. Temperatures approximating and higher than the melting point of the unirradiated crystalline polyyne will effect a color transformation of the initial radiant-energy induced colored polyyne crystals, but in so doing there may be some loss in sharpness of the image with some blurring and roughing of the image border or periphery. This can be avoided, or at least minimized, if the colored crystal portions and crystals are firmly held at these temperatures so as to avoid being overcoated or dissolved in melted unexposed polyyne.

Another manner for effecting color transformation of the initial color image is exposure to a solvent for the unexposed polyyne. An exposure for about 10 to 15 seconds at an elevated temperature from about 5 to 10 lower than employable for heat fixing generally is satisfactory. Methanol, ethanol, toluene, diethyl ether, butyl acetate, carbon tetrachloride, acetone, 2butoxyethanol, and like solvents are useful. Water vapor and aqueous solutions, such as aqueous hydrochloric acid, are useful with water soluble polyyne derivatives. Other useful solvents also will be apparent. I

An advantage of the element having the image thereof in a distinctly different color than' the initial radiation-induced color, is that this other color may be more susceptible to providing print-out copies with good contrast when prints, negatives, and the like, of this image are made by conventional silver halide photographic techniques.

As indicated above, image recording elements utilizing radiation sensitive polyynes may be prepared by fixing the crystalline polyyne on-a surface. This may be done, for example, by coating a dispersion of the polyyne in a polymer matrix on a suitable support, by coating a solution of the polyyne in a polymer solution and allowing the polyyne to crystalline upon solvent evaporation, by applying a solution of a polyyne to a paper surface and allowing the polyyne to crystallize upon the fibers, by coating a dispersion of a water immiscible polyyne solution in an aqueous binder and allowing evaporation to form polyyne crystals in the binder matrix, or by simply smearing the polyyne crystals on a suitable support. I

A particularly advantageous technique for preparing radiation-sensitive elements according to this invention is by the dissolution of radiation-sensitive polyyne crystals in one or more substantially water-immiscible organic solvents (i.e., about -25 percent soluble in water, by weight) which are then added to an aqueous solution of a hydrophilic binder. The water-immiscible polyyne solution is then dispersed in the aqueous binder solution, which may also contain a suitable surfactant, and mechanically stirred such as by means of a homogenizer or ultrasonic agitator, to form an oil-. in-water dispersion, substantially devoid of polyyne crystals. This dispersion is then coated on a suitable support, during which coating the water-immiscible solvent evaporates from the coating with concomitant production of extremely fine crystals of the polyyne, uniformly distributed in the coated hydrophilic carrier. The polyyne elements thus formed are highly sensitive to various forms of radiation, are extremely uniform in particle size, and are very stable. It is desirable that the organic solvent employed to dissolve the polyacetylenic compound according to this technique be waterimmiscible, or essentially so. Thus, solvents having solubilit'ies in water of from 0 to about 25 percent are suitable. Exemplary organic solvents include cyclohexanone, ethyl acetate, cyclohexane, dichloromethane, dichloroethane, chloroform, pentyl alcohol, hexyl alcohol, 4methyl2-pentanone, benzene, toluene and the like, and mixtures thereof. Varying amounts of solvent may be employed, but generally, from 1 to units (by weight) of solvent may be employed for each unit of polyacetylene to be used, with from 2 to 3 times as much solvent as polyyne being the preferred range. if water-miscible solvents are employed, an immediate precipitation of dissolved polyyne occurs upon mixing of solvent and aqueous binder solutions, resulting in relatively large average grain size, and accordingly, lower stability and control.

The time required for complete dispersion may vary from several seconds to several hours, dependent upon dispersal technique, materials employed, andsize of dispersed phase droplets desired. In general, crystals averaging 1 micron in cross section, may be obtained from an emulsion formed by ultrasonically dispersing a polyyne solution in an aqueous binder for one to two minutes. It is to be recognized, however, that blending time may be so selected as to achieve the desired results in accordance with the specific materials employed.

Varying amounts of the polyyne and/or binder material may be chosen, dependent upon anticipated use of the elements produced, among other factors. In general, polyyne to binder ratios (by weight) may range from about 0.1 to about 3.0 or higher. in terms of coating density, sufficient polyyne may be utilized to provide from about to 2,000 mg of polyyne per square foot of coated element. As indicated, the amount of polyyne employed is quite widely variable, and may be varied to suit the desired utilization, binder, and solvent employed.

In preparing the sensitized elements of this invention, the sensitizing material may be separately dispersed in the solvent employed to dissolve the polyacetylenic compound, and added to the aqueous binder solution with the polyacetylenic solution. Alternatively, the organometallic sensitizer may be separately dispersed in the aqueous binder solution.

The amount of sensitizer which can be added to a particular composition to give optimum sensitization can vary widely. The optimum amount will, of course, vary with the polyyne employed as well as with the particular sensitizing compound. In general, substantial gains can be obtained where an appropriate sensitizer is added at a concentration in a range of from about to about 750 percent by weight, based on the weight of the polyyne, and preferably from about 200 to about 500 percent, by weight, although more or less of the sensitizer may be employed if desired.

After blending, the polyacetylenic compound is present in the aqueous binder solution in the form of finely divided, discrete globules of dissolved polyacetylene, which are essentially insoluble in the continuous phase. This emulsion is quite stable, and may be stored for considerable lengths of time before utilization without settling, agglomeration, or breaking.

Radiation-sensitive elements may be prepared by coating the thus formed emulsion upon a suitable support and evaporating the dispersed solvent phase. Any suitable coating means may be employed, such as dip coating, air knife coating, curtain coating, flow coating, bar coating, etc. The coating may be chill set, for ease of handling, if so desired, or allowed to dry to a solid continuous phase at room temperature. During the drying stage, the organic solvent volatilizes, causing the precipitation of discrete particles of radiation-sensitive crystalline polyacetylenic compound.

In addition to comingling in a solvent and subsequent crystal formation, other suitable sensitization techniques include fusion of the sensitizer with the polyyne; adsorption of the sensitizer to the surface of the polyyne; and presence of the sensitizer in the matrix surrounding the polyyne crystals.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS This invention is further illustrated by the following examples.

EXAMPLE I Formulation, Sample D CH OOC(CH ),,C E C-C 0.3 gm =C(CH,),,COOH Polystyrene 2.1 gm Triphenylbismuthine 0.6 gm Toluene 25.0 i

An aliquot portion of this dispersion is coated on a poly(ethylene terephthalate) film support and air dried, in the dark, to yield a dry thickness of approximately 30 11 Control samples prepared from the following formulations are prepared and coated in similar manner.

Formulation Sample A Polystyrene 3.0 gm Toluene 25.0 ml

Table ll Feature igogg. in Weight Triphenyl- Hexaphenyl- Optical Sample Polyync Polystyrene bismuthine dilead Density E 100% 0% 0% 0.03 F 0% 75% 25% 0% 0.03 G i 0% 75% 0% 25% 0.03 H 90% 0% 0% 0.22 l 10% 70% 0% 0.32 J 10% 70% 0% 20% 0.32

' samsisasaapiaf Polystyrene 2.25 gm Triphenylbismuthine 0.75 gm Toluene 25.0 ml

Formulation, Sample C CH,,OOC(CH,)..C I C-C 0.3 gm -C(CH,),.COOH Polystyrene 2.7 gm Toluene 25.0 ml

7 Each of thes e samples is then eitposed to a dirk}? x-ray source of 50 KV, 4O ma, for 100 sec. while thesample is positioned 3 inches away from the source. The following density results are obtained. printout density being measured by means of a Macbeth Quantalog Densitometer, model TD 404-39, using Kodak Status A filters, with A optical density beingthe difference between image density and background density.

Table 1 Feature (cone. in Weight A Sample Polyyne Polystyrene Triphenyl- Optical bismuthine Density A 0 r00 7. 0 0.0 B 0 75% 0.0 c 10% 90% 0 0.02 D 10% 70% 20% 0.43

EXAMPLE 2 The data below demonstrate the utility of a radiationsensitive polyacetylenic metal salt, Barium l0,l2--docosadiynedioate, in combination with an organometallic sensitizer. These conditions and coatings are as described in Example 1.

As clearly indicated by the above examples, a considerable increase in x-ray sensitivity of both the monomethyl ester and the barium salt of 10.12- docosadiynedioic acid is achieved by the addition of an organometallic compound. Similar results are obtained when other polyacetylenic compounds are employed using such organometallic sensitizing addenda astriphenylbismuthine, hexaphenyldilead, [(C H Sn] Te; ti 5)a s 5)3; s 5) s 5)ai s 5) ]2 6 4)2 g 4 g =1;

and (C6H4 )gTeg.

The invention has been described in detail with particular reference to certain preferred embodiments thereto, but it will be understood that variations and modifications can be effected with the spirit and scope of the invention.

I claim:

l. A composition comprising a radiation-sensitive polyacetylenic compound and a sensitizing amount of an organo-metallic compound selected from the group consisting of triphenylbismuthine, hexaphenyldilead, 6 5)3 ]2 s sh M s sh ti 5)3 fi 5)3s 6 5) ]2 s sl lz G 4 2 g1 6 5 g 31 and s 4)2 2- 2. A composition as set forth in claim 1, wherein said polyacetylenic compound has a minimum of two acetylenic linkages as a conjugated system.

3. Acomposition as set forth in claim 1, wherein said polyacetylenic compound is selected from the group consisting of lower alkyl esters of diyne dioic acid, polyacetylenic polyoic acid alkylamides, polyacetylenic amine salts, and diyne diol urethanes.

4. A composition comprising a radiation-sensitive polyacetylenic compound and a sensitizing amount of triphenylbismuthine.

5. A composition comprising a radiation-sensitive polyacetylenic compound and a sensitizing amount of hexaphenyldilead.

6. An element comprising a carrier, a radiationsensitive polyacetylenic compound, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismuthine, hexa- 7. An element as set forth in claim 6, wherein said carrier comprises a support to which is adhered a binder having said polyacetylenic compound dispersed therein.

8. An element as set forth in claim 7, wherein said polyacetylenic compound has a minimum of two acetylenic linkages as a conjugated system.

9. An element as set forth in claim 8, wherein said binder is gelatin.

10. An element as set forth in claim 6, wherein. said polyacetylenic compound is selected from the group consisting of lower alkyl esters of diyne dioic acid, polyacetylenic polyoic acid alkylamides, polyacetylenic amine salts, and diyne diol urethanes.

11. An element comprising a carrier, a radiationsensitive polyacetylenic compound, and a sensitizing amount of triphenylbismuthine. I

12. An element comprising a carrier, a radiationsensitive polyacetylenic compound, and a sensitizing amount of hexaphenyldilead.

13. An element comprising a carrier, a radiationsensitive polyacetylenic compound having a minimum of two acetylenic linkages as a conjugated system, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismu- 14. An element comprising a support having coated thereon a layer comprising a binder, a radiationsensitive lower alkyl ester of diyne dioic acid, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismuthine, hexaphenyldilead, 6 )3 6 5)3! s 5)3 6 5)3, [(C H5)Pb]2T, (C H4)2Hg, C6H5HgOCOCH3, and s fiz z' 15. An element as set forth in claim 14, wherein said ester is the monomethyl ester of 10,l2docosadiyne dioic acid.

16. An element comprising a support having coated thereon a layer comprising a binder, a radiationsensitive polyacetylenic amine salt, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexaphenyldilead, [(C H Sn] Te, a s )a s 5 )3, s 5)a 6 5)3a G Q h 6 4)2 g s s g m and a 4)2 2- monium I organometallic compound 17. An element as set forth in claim 16, wherein said polyacetylenic amine salt is selected from the group consisting of hexylammonium 20-(Nhexylcarbamoyl)9,l leicosadiyne l -carboxylate, propylam- 20(N-propylcarbamoyl)9,l l eicosadiyne 1 -carboxylate, and 3hydroxypropylammonium 20-[N( 3hydroxypropyl)carbamoyl 1-9, 1 l-eicosadiyne 1 carboxylate.

18. An element comprising a support having coated thereon a layer comprising a binder, a radiationsensitive polyacetylenic alkylamide, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexa- 19. An element as set forth in claim 18, wherein said alkylamide is selected from the group consisting of methyl 2 l N-( 3-carboxypropyl)carbamoyl1-- 0,- 12-heneicosadiyne; methyl 2 l -[N( 3- hydroxypropyl)carbamoyl1-10, l 2-heneicosadiynoate; and methyl 2l'-[N(3-carboxypropyl)carbamoyl] l0, 1 2-heneicosadiynoate.

20. An element comprising a support having coated thereon a layer comprising a binder, a radiationsensitive polyacetylenic bis urethane, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexaphenyldilead, [(C l-l Sn] Te, (C H GeTeSn(C H 1h 6 5)3 6 5)s, G Q h fi Uz' g, C6H5HgOCOCH3, and (C6H4)2T62.

21. An element asset forth in claim 20, wherein said bis urethane is 2,4hexadiynel,6-diol bis(- N--hexylurethane).

22. An element as set forth in claim 20, wherein said is phenyl substituted. 

2. A composition as set forth in claim 1, wherein said polyacetylenic compound has a minimum of two acetylenic linkages as a conjugated system.
 3. A composition as set forth in claim 1, wherein said polyacetylenic compound is selected from the group consisting of lower alkyl esters of diyne dioic acid, polyacetylenic polyoic acid alkylamides, polyacetylenic amine salts, and diyne diol urethanes.
 4. A composition comprising a radiation-sensitive polyacetylenic compound and a sensitizing amount of triphenylbismuthine.
 5. A composition comprising a radiation-sensitive polyacetylenic compound and a sensitizing amount of hexaphenyldilead.
 6. An element comprising a carrier, a radiation-sensitive polyacetylenic compound, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 7. An element as set forth in claim 6, wherein said carrier comprises a support to which is adhered a binder having said polyacetylenic compound dispersed therein.
 8. An element as set forth in claim 7, wherein said polyacetylenic compound has a minimum of two acetylenic linkages as a conjugated system.
 9. An element as set forth in claim 8, wherein said binder is gelatin.
 10. An element as set forth in claim 6, wherein said polyacetylenic compound is selected from the group consisting of lower alkyl esters of diyne dioic acid, polyacetylenic polyoic acid alkylamides, polyacetylenic amine salts, and diyne diol urethanes.
 11. An element comprising a carrier, a radiation-sensitive polyacetylenic compound, and a sensitizing amount of triphenylbismuthine.
 12. An element comprising a carrier, a radiation-sensitive polyacetylenic compound, and a sensitizing amount of hexaphenyldilead.
 13. An element comprising a carrier, a radiation-sensitive polyacetylenic compound having a minimum of two acetylenic linkages as a conjugated system, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 14. An element comprising a support having coated thereon a layer comprising a binder, a radiation-sensitive lower alkyl ester of diyne dioic acid, and a sensitizing amount of an organometallic compound selected from the group consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 15. An element as set forth in claim 14, wherein said ester is the monomethyl ester of 10,12-docosadiyne dioic acid.
 16. An element comprisIng a support having coated thereon a layer comprising a binder, a radiation-sensitive polyacetylenic amine salt, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 17. An element as set forth in claim 16, wherein said polyacetylenic amine salt is selected from the group consisting of hexylammonium 20-(N-hexylcarbamoyl)-9,11-eicosadiyne-1-carboxylate, propylammonium 20-(N-propylcarbamoyl)-9,11-eicosadiyne-1-carboxylate, and 3-hydroxypropylammonium 20-(N-(3-hydroxypropyl)carbamoyl)-9,11-eicosadiyne-1-carboxylate.
 18. An element comprising a support having coated thereon a layer comprising a binder, a radiation-sensitive polyacetylenic alkylamide, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 19. An element as set forth in claim 18, wherein said alkylamide is selected from the group consisting of methyl 21-(N-(3-carboxypropyl)carbamoyl)-10,12-heneicosadiyne; methyl 21-(N-(3-hydroxypropyl)carbamoyl)-10,12-heneicosadiynoate; and methyl 21-(N-(3-carboxypropyl)carbamoyl)-10,12-heneicosadiynoate.
 20. An element comprising a support having coated thereon a layer comprising a binder, a radiation-sensitive polyacetylenic bis urethane, and a sensitizing amount of an organometallic compound selected from the class consisting of triphenylbismuthine, hexaphenyldilead, ((C6H5)3Sn)2Te, (C6H5)3GeTeSn(C6H5)3, (C6H5)3SnTePb(C6H5)3, ((C6H5)Pb)2Te, (C6H4)2Hg, C6H5HgOCOCH3, and (C6H4)2Te2.
 21. An element as set forth in claim 20, wherein said bis urethane is 2,4-hexadiyne-1,6-diol bis(N-hexylurethane).
 22. An element as set forth in claim 20, wherein said organometallic compound is phenyl substituted. 